INFEWS: N/P/H20: From Antinutrients to Water Pollutants: Exploring the Behavior of Polyphosphate Anions in Aqueous Solutions

植酸盐是一种常见的分子，存在于玉米皮和其他植物材料中。食物中的二氯苯酚会干扰许多动物（包括猪和鸡）消化道对营养素的吸收。结果，动物饲料中存在的蛋白质和重要金属离子变得不可用，导致从这些动物制成的肉类产品的效率大大降低。在美国国家科学基金会化学部大分子、超分子和纳米化学项目的支持下，Paul S。宾夕法尼亚州立大学的Cremer正在研究植酸盐和类似的阴离子（带有额外负电荷的分子），以了解它们与金属离子的相互作用，并了解这些高度带负电荷的物质如何导致蛋白质和其他大分子从水溶液中沉淀出来。这项工作不仅有助于阐明如何更有效地利用牲畜饲料，而且还有助于培养化学科学方面的研究生和本科生。这些研究的简化版本被用作更新课程和实验室的跳板，用于教授高中生分子间力和非共价相互作用。Cremer小组正在探索植酸盐和二价金属阳离子在水溶液中的相互作用。各种阳离子和单个磷酸基团之间的相互作用通常是相似的，但当金属离子同时与多个磷酸基团相互作用时，这种相互作用会发生显著变化，其中离子可以桥接相邻的磷酸基团。离子结合的热力学正与聚阴离子的水合壳，可以通过拉曼和振动和频光谱获得的信息。这些研究也被扩展到了解离子结合和水合水结构如何影响蛋白质和多肽从水溶液中的盐析，作为pH值，盐浓度和特定阳离子身份的函数。除了肌醇六磷酸盐，它包含围绕肌醇环的六个磷酸基团，正在进行的研究与一至五个磷酸基团放置在环周围具有特定的立体化学。测量也正在与磷脂酰肌醇脂质在平面膜格式，以阐明在结合行为的多磷酸基团结合到表面和那些在本体溶液中的差异。

Phytate is a common molecule found in the husks of corn, as well as other plant materials. Its presence in food can interfere with the adsorption of nutrients in the digestive track of many animals, including pigs and chickens. As a result, proteins and vital metal ions present in the animals' feed are rendered unavailable, causing an enormous loss in efficiency in the meat products made from these animals. With the support from the Macromolecular, Supramolecular and Nanochemistry Program of the NSF Chemistry Division, Prof. Paul S. Cremer at the Pennsylvania State University is studying phytate and similar anions (molecules with extra negative charge) to understand their interactions with metal ions and to learn how these highly negatively charged species cause the precipitation of proteins and other large molecules from water solutions. This work not only helps shed light on how livestock feed can be used more efficiently, but also helps train graduate and undergraduate students in the chemical sciences. Simplified versions of these studies are being used as a springboard to update the curriculum and laboratories used to teach high school students about intermolecular forces and non-covalent interactions. The Cremer group is exploring interactions between phytate and divalent metal cations in aqueous solutions. The interactions between various cations and individual phosphate groups are often similar, but this changes markedly when metal ions interact simultaneously with multiple phosphate groups, where the ions can bridge adjacent phosphate moieties. The thermodynamics of ion binding is being correlated with information on the polyanion's hydration shell that can be obtained by Raman and vibrational sum frequency spectroscopy. Such studies are also being extended to understand how ion binding and hydration water structures affect the salting out of proteins and polypeptides from aqueous solutions as a function of pH, salt concentration, and specific cation identity. In addition to phytate, which contains six phosphate groups around an inositol ring, studies are being performed with one through five phosphate groups placed around the ring with specific stereochemistry. Measurements are also being made with phosphatidylinositol lipids in planar membrane formats to elucidate the difference in binding behavior of polyphosphate groups bound to surfaces and those in bulk solution.